import java.util.HashSet;

public class singleton {
    
    private static singleton Instance;
    
    private singleton() {}
    
    private static singleton getInstance() {
        if (Instance == null) {
            return new singleton();
        }
        return Instance;
    }

    public static void main(String[] args) {
        singleton instance = getInstance();
        System.out.println(instance);
        HashSet<Integer> set = new HashSet<>();
        String s = "s";
        s.length();
        char[] chars = {'1', '2', '3', '4', '5', '6', '7', '8'};
        String string = chars.toString();
        String s1 = new String(chars, 0, 5);
        System.out.println(s1);
    }
}
